Navigated Brainstem Monitoring in the Rhomboid Fossa

Monitoring of cranial nerve function during intrinsic brainstem surgery is crucial in order to avoid iatrogenic morbidity. The combination of neuronavigation and cranial nerve monitoring might offer a tool for the understanding of the sometimes complex anatomy of brainstem nuclei. In an intraoperative environment we have stimulated the surface of the rhomboid fossa in patients suffering from intrinsic brainstem lesions (cavernous malformations). EMG recording of the muscles innervated by the cranial nerve was performed (Nicolet, Germany, Viking IV). Once a nucleus was outlined by this technique, the exact point…